Poly Brominated Diphenyl Ethers (PBDEs) are known flame retardants with highly persistent and lipophilic in nature. The continued usage of PBDE in various products amplifies the human burden of PBDEs. It is therefore, important to study the potential toxicological and/or biological effects of PBDE exposure in human. In this study we investigated the mode of action of PBDE induced toxicity in human liver by exposing human hepatocarcinoma cells in a time (24-72h) and dose (0-100μM) dependent manner. The highest test dose caused an inhibition in cell viability up to 50% after 72h, whereas lower doses (<50μM) showed slight increase in cell viability. Likewise, higher doses caused significant accumulation of intracellular ROS over time. Further, increase in caspase-3 enzyme levels and DNA fragmentation showed that, lower brominated PBDEs induce liver toxicity through accumulation of toxic metabolites and reactive oxygen species over time leading to caspase-mediated apoptotic cell death.

In the recent years, many research articles focused on endocrine disrupting compounds in the environment. Some of these compounds are listed in a group named brominated flame retardants. However, only few articles investigated endocrine activity of several "new" brominated flame retardants. These chemicals such as 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) or bis(2-ethylhexyl) tetrabromophthalate (TBPH) are newly used due to ban of some previously most produced brominated flame retardant mixes. In this study, we used two recombinant yeast screens to measure estrogenic, androgenic, antiestrognic and antiandrogenic activities of some alternative brominated flame retardants. We also used ligninolytic fungi to investigate biodegradation of these compounds. Our results suggest, that 2,4,6-tribromophenol (TBP) may be a new environmental endocrine disruptor. This substance showed antiestrogenic and antiandrogenic activity in our tests. 1,2-bis(2,4,6- tribromophenoxy)ethane (BTBPE) had certain antagonistic activity too. In the biodegradation experiment, only three compounds showed significant degradation during the test period. No biodegradation have been observed for other compounds. In this study, we applied gas chromatography with mass spectrometry to analyze these "new" flame retardants. Method for gas...

The target of my diploma thesis is evaluation of soil load by polybrominated diphenylethers. This is the soils, which were affected by fire and comparsion with load by soils, which were not affected by fire. In teoretical part available informations about BDE from various sources are processed. Target of practical part is find the optimal method for determination BDE, verification of her yield a determination of reals samples with using this method. In the end this thesis contains measured results, its interpetation in tables, graphes and evaluation of load by individual congeners. Key is comparsion load of soils, which were affected and which were not affected by fire. BDE are released during the fire and we can decide that soils which were caused by fire should be contaminated more, than soils, which were not caused by fire.

<p> A quantitative study is made of the relative sensitivity of Phaseolus vulgaris var. Pinto to several different growth retardants, and to treatment of retarded plants with GA3. The growth of progeny from retarded plants is exam!ned and the cause of the transfer phenomenon is determined to be transfer of the growth retardants themselves to the progeny via the seeds, in some cases through to a third generation. </p> / Thesis / Master of Science (MSc)

No description available.

No description available.

Trä som byggnadsmaterial har ökat inom byggbranschen de senaste åren. Detta på grund av att trä är ett miljövänligt och förnybart material. Dock ställer trä som byggnadsmaterial en hel del utmaningar då trä är brandkänsligt och kan behöva brandskydds-behandlas innan användning. Detta görs för att minska risken för uppkomst av brand och kan göras på två sätt, antingen genom att brandskyddsimpregnera eller flamskyddsmåla träprodukten. Den främsta uppgiften brandskyddsmedel har är i det tidiga skeendet av brand då det kan förlänga tiden till antändning. Funktionen brandskyddsbehandlingen har på träprodukten kan över tid minska och kan variera kraftigt i dess duglighet. Tillvägagångsätten för att bestämma brandskyddsbehandlade träprodukters beständighet över tid är olika och det tas kontinuerligt fram olika studier, forskning och experiment. 2017 fastställdes en europeisk standard, EN 16755, som innehåller olika bruksklasser för brandskyddets beständighet. Standard togs framför att hjälpa och ge vägledning till användare för att hitta passande brandskyddade produkter och motivera tillverkarna till att producera och leverera bra produkter.I detta arbete har flera olika studier granskats och studerats över vilka brandegenskaper som förändras när brandskyddsbehandlade träfasader exponeras för utomhusklimat. Tre studier har utfört accelererad och naturlig åldring där huvudsyftet har varit att se hur träets beständighet förändras över tid. Andra studier har studerat och testat vilka egenskaper brandhämmandekemikalier har för träprodukten. Melaminformaldehydharts, borsyra och guanylureafosfatanvänds som brandhämmande kemikalie för att nämna några. Slutsatsen drogs att brandskyddsmedel kan avsevärt förbättra brandegenskaperna genom att förlänga antändningstiden, ge högre LOI-värden och ge lägre värmeavgivningshastighet, HRR. LOI är ett syreindex som är ett index för hur mycket syre som krävs för förbränning av träet. Men över tid minskar brandskyddet och dess funktion förloras då brandskyddsmedlet lakas ut från träprodukten. En av studierna använde predikteringsmodeller för att utvärdera vilken klass träpanelerna som har utsatts för naturlig åldring har. Studien klassade träpanelerna i euroklass D eller lägre. Vilket motsvarar samma klass som obehandlade och omålade träpaneler

<p>Accumulating evidence is suggesting that exposure to some environmental contaminants may alter adipogenesis, resulting in accumulation of adipocytes, and often significant weight gain. Thus these types of contaminants are often referred to as obesogens. Many of these contaminants act via the activation (i.e. agonism) of the peroxisome proliferator activated receptor &#947; (PPAR&#947;) nuclear receptor. To date, very few chemicals have been identified as possible PPAR&#61543; ligands. In the thesis, our goal was to determine the PPAR&#947; ligand binding potency and activation of several groups of major semi-volatile organic compounds (SVOCs) that are ubiquitously detected in indoor environments, including flame retardants such as polybrominated diphenyl ethers (PBDEs) and Firemaster 550 (FM550), and other SVOCs such as phthalates, organotins, halogenated phenols and bisphenols. Additional attention was also given to the potential activity of the major metabolites of several of these compounds. Since the primary sink for many of these SVOCs is dust, and dust ingestion has been confirmed as an important pathway for SVOCs accumulation in humans, the potential PPAR&#61543; binding and activation in extracts from environmentally relevant dust samples was also investigated. </p><p> Previous studies have also shown that SVOCs sorbed to organic matrices (e.g., soil and sediment), were only partially bioaccessible (bioavailable), but it was unclear how bioaccessible these compounds are from indoor dust matrices. In addition, bioactivation of SVOCs (via metabolism) could exacerbate their PPAR&#61543; potency. Therefore, to adequately assess the potential risk of PPAR&#947; activation from exposure to SVOC mixtures in house dust, it is essential that one also investigates the bioaccessibility and bioactivation of these chemicals following ingestion. </p><p> In the first research aim of this thesis, the bioaccessibility and bioactivation of several important SVOCs in house dust was investigated. To accomplish this, Tenax beads (TA) encapsulated within a stainless steel insert were used as an infinite adsorption sink to estimate the dynamic absorption of a suite of flame retardants (FRs) commonly detected in indoor dust samples, and from a few polyurethane foam samples for comparison. Experimental results demonstrate that the bioaccessibility and stability of FRs following ingestion varies both by chemical and by matrix. Organophosphate flame retardants (OPFRs) had the highest estimated bioaccessibility (~80%) compared to brominated compounds (e.g. PBDEs), and values generally decreased with increasing Log Kow, with <30% bioaccessibility measured for the most hydrophobic compound tested, BDE209. In addition, the stability of the more labile SVOCs that contained ester groups (e.g. OPFRs and 2-ethylhexyl-tetrabromo-benzoate (TBB)) were examined in a simulated digestive fluid matrix. No significant changes in the OPFR concentrations were observed in this fluid; however, TBB was found to readily hydrolyze to tetrabromobenzoic acid (TBBA) in the intestinal fluid in the presence of lipases. </p><p> In research aims 2 and 3, two commercially available high-throughput bioassays, a fluorescence polarization PPAR&#61543; ligand binding assay (PolarScreenTM PPAR&#947;-competitor assay kit, Invitrogen, Aim 2) and a PPAR&#61543; reporter gene assay (GeneBLAzer PPAR&#947; non-DA Assay, Invitrogen, Aim 3) were used to investigate the binding potency and activation of several groups of SVOCs and dust extracts with human PPAR&#947; LBD; respectively. In the PPAR&#61543; binding assay (Aim 2), most of the tested compounds exhibited dose-dependent binding to PPAR&#947;. Mono(2-ethylhexyl) tetrabromophthalate (TB-MEHP), halogenated bisphenol/phenols, triphenyl phosphate and hydroxylated PBDEs were found to be potent or moderate PPAR&#947; ligands, based on the measured ligand binding dissociation constant (Kd). The most potent compound was 3-OH-BDE47, with an IC50 of 0.24 &#956;M. The extent of halogenation and the position of the hydroxyl group strongly affected binding. Of the dust samples tested, 21 of 24 samples showed significant PPAR&#61543; binding potency at a concentration of 3 mg dust equivalents (DEQ)/mL. In the PPAR&#61543; reporter assay (Aim 3), many SVOCs or their metabolites were either confirmed (based on previous reports) or for the first time were found to be potential PPAR&#947; agonists with various potency and efficacy. We also observed that 15 of 25 dust extracts examined showed an activation percentage more than 8% (calculated activation threshold) of the maximal activation induced by rosiglitazone (positive control). In some cases, activation was as high as 50% of the rosiglitazone activation for the dust extracts with the highest efficacy. Furthermore, the correlation between the reporter assay and the ligand binding assay among the house dust extracts was significant and positive (r = 0.7, p < 0.003), suggesting the binding potency was predicting activation. In research aim 2, the effect of bioactivation on the PPAR&#947; binding potency was also investigated. In vitro bioactivation of house dust extracts incubated with rat and human hepatic S9 fractions was used to investigate the role of in vivo biotransformation on PPAR gamma activity. The result showed that metabolism may lead to an increased binding affinity, as a 3-16% increase in PPAR&#947; binding activity was observed following bioactivation of the dust extracts.</p><p> In research aim 4, an effect-directed analysis (EDA) was used to identify compounds likely contributing to the observed PPAR&#61543; activity among the dust extract. Three dust extracts which showed significant PPAR&#61543; activity with approximately 25, 30, and 50% of the maximal response induced by rosiglitazone at the highest efficacy were fractionated using normal phase high-performance liquid chromatography (NP-HPLC) and each fraction was individually tested for PPAR&#61543; activity. Active fractions were then analyzed using gas-chromatography mass spectrometry (GC-MS) and possible compounds identified. Three dust extracts showed a similar PPAR&#61543; activity distribution among the NP-HPLC fractions. In the most active fractions, fatty acids (FAs) were identified as the most active chemicals. The concentrations of four FAs were measured in the house dust extracts, and the concentrations were found to be highly correlated with the observed PPAR&#61543; activity. These four FAs were also tested for PPAR&#61543; activity and found to be partial PPAR&#61543; agonists, particularly oleic and myristic acid. To tentatively identify sources of FAs, FAs in human/animal hair, dead skin cells, and two brands of cooking oil were analyzed. We found the same FAs in those samples and there concentrations were relatively abundant, ranging from 186 to 14,868 µg/g. Therefore, these results suggest that FAs are likely responsible for the observed PPAR&#61543; activity in indoor dust. Also, this is the first study reporting on the level of FAs in dust samples. The source of these FAs in dust may be either from the cooking or accumulation of human/animal cells in indoor dust.</p><p> In conclusion, this research demonstrates that many SVOCs ubiqutiously detected in house dust, and/or their metabolites, can be weak or moderate PPAR&#61543; ligands. In addition, chemical mixtures in house dust can effectively bind to and activate PPAR&#61543;. However, our results suggest FAs are probably responsible for these observations, and likely outcompeting the synthetic environmental contaminants present in the dust extract. Furthermore, bioactivation of contaminants present in house dust can potentially increase their affinity for PPAR&#61543;. And lastly, the bioaccessibility and stability of SVOCs in house dust after ingestion are likely to modulate the PPAR&#61543; activity in the environmental mixtures and should be considered in future risk assessments.</p> / Dissertation

Rapid economic development has occurred during the past few decades in China with the Yangtze River Delta (YRD) area as one of the most progressive areas. The urbanization, industrialization, agricultural and aquaculture activities result in extensive production and application of chemicals. Organohalogen contaminants (OHCs) have been widely used as i.e. pesticides, flame retardants and plasticizers. They are persistent, bioaccumulative and pose a potential threat to ecosystem and human health. However, limited research has been conducted in the YRD with respect to chemicals environmental exposure. The main objective of this thesis is to investigate the contamination level, distribution pattern and sources of OHCs in the YRD. Wildlife from different habitats are used to indicate the environmental pollution situation, and evaluate selected matrices for use in long term biomonitoring to determine the environmental stress the contamination may cause. In addition, a method is developed for dicofol analysis. Moreover, a specific effort is made to introduce statistic power analysis to assist in optimal sampling design. The thesis results show extensive contamination of OHCs in wildlife in the YRD. The occurrences of high concentrations of chlorinated paraffins (CPs) are reported in wildlife, in particular in terrestrial species, (i.e. short-tailed mamushi snake and peregrine falcon). Impurities and byproducts of pentachlorophenol products, i.e. polychlorinated diphenyl ethers (PCDEs) and hydroxylated polychlorinated diphenyl ethers (OH-PCDEs) are identified and reported for the first time in eggs from black-crowned night heron and whiskered tern. High concentrations of octachlorodibenzo-p-dioxin (OCDD) are determined in these samples. The toxic equivalents (TEQs) of polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzofurans (PCDFs) are at mean levels of 300 and 520 pg TEQ g-1lw (WHO2005 TEQ) in eggs from the two bird species, respectively. This is two orders of magnitude higher than European Union (EU) regulation limit in chicken eggs. Also, a novel pattern of polychlorinated biphenyls (PCBs) with octa- to decaCBs, contributing to as much as 20% of total PCBs therein, are reported in birds. The legacy POPs shows a common characteristic with relatively high level of organochlorine pesticides (i.e. DDT, hexacyclohexanes (HCHs) and Mirex), indicating historic applications. In contrast, rather low concentrations are shown of industrial chemicals such as PCBs and polybrominated diphenyl ethers (PBDEs). A refined and improved analytical method is developed to separate dicofol from its major decomposition compound, 4,4’-dichlorobenzophenone. Hence dicofol is possible to assess as such. Statistic power analysis demonstrates that sampling of sedentary species should be consistently spread over a larger area to monitor temporal trends of contaminants in a robust manner. The results presented in this thesis show high CPs and OCDD concentrations in wildlife. The levels and patterns of OHCs in YRD differ from other well studied areas of the world. This is likely due to the extensive production and use of chemicals in the YRD. The results strongly signal the need of research biomonitoring programs that meet the current situation of the YRD. Such programs will contribute to the management of chemicals and environment in YRD, with the potential to grow into the human health sector, and to expand to China as a whole. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 5: Submitted. Paper 6: Manuscript.</p><p> </p>

Este trabalho teve como objetivo avaliar a influência de diferentes relações de fósforo (P) e potássio (K) nos aspectos morfológicos, fisiológicos, e nos parâmetros produtivos de plantas de soja tratadas com o retardador de crescimento TIBA, através da análise das variáveis altura, número de ramificações (primárias, secundárias e total), massa seca de raíz, valor SPAD (clorofilas), atividade enzimática da ascorbato peroxidase (APX), guaiacol peroxidase (GPX), nitrato redutase (NR), fenilalanina amonia liase (PAL), concentração de proteína total solúvel (PTS), assim como do número de vagens e grãos, massa de grãos e massa média de 100 grãos (referentes a haste, ramificações e total). Foram conduzidos dois experimentos em casa de vegetação, em sistema hidropônico (vasos plásticos contendo areia lavada, com adição de soluções nutritivas modificadas de Hoagland). Utilizou-se o cultivar BRS 255RR, através do delineamento casualizado em blocos, em esquema fatorial 2 x 4, constituído por 2 níveis de TIBA (0 e 30 mg L-1) e 4 relações dos nutrientes P e K (0,5, 1,0, 1,5 e 2,0 vezes o teor desses nutrientes na solução original de Hoagland). Para as variáveis altura, valor SPAD, atividade enzimática e concentração de PTS, considerou-se a adição do fator tempo em nível de sub-parcela. A unidade experimental foi constituída por um vaso de polietileno, com duas plantas de soja. A aplicação do TIBA foi realizada via pulverização foliar, no estádio V5, enquanto que o fornecimento das soluções nutritivas teve início a partir do 4º dia após a emergência. O TIBA promoveu a redução da altura final das plantas e da massa seca de raíz, além de promover o incremento do valor SPAD no período de transição entre as fases vegetativa e reprodutiva. Esse retardador não exerce efeito sobre os valores totais das variáveis número de vagens e grãos, massa de grãos e massa média de 100 grãos, porém, apresenta efeito sobre alguns de seus constituíntes (aumento no número de ramificações secundárias e diminuição no número de vagens e grãos e massa de grãos das ramificações). A relação de P e K igual a 2,0 afeta negativamente a maior parte das variáveis e alguns de seus constituíntes (altura, massa seca de raíz, número de ramificações primárias e total, número total de vagens e grãos, número de grãos da haste, massa de grãos da haste e total), enquanto que a relação de 1,5 afeta o número de vagens das ramificações e a massa média total de 100 grãos, respectivamente. / This study aimed to evaluate the influence of different ratios of phosphorus (P) and potassium (K) in morphological, physiological and productive performance of soybean plants treated with growth retardant TIBA, through the analysis of height, number of branches (primary, secondary and total), root dry weight, SPAD (chlorophyll) value, enzymatic activity of ascorbate peroxidase (APX), guaiacol peroxidase (GPX), nitrate redutase (NR), phenylalanine ammonia lyase (PAL), concentration of total soluble protein (TSP), as well as the number of pods and grains, weight of grains and average weight of 100 grains (refer to stem, branches and total). Two experiments were conducted under greenhouse conditions in a hydroponic system (plastic pots containing washed sand, with the addition of modified Hoagland nutrient solution). Were used the cultivar BRS 255RR, by randomized block design, in a factorial 2 x 4, consisting of two levels of TIBA (0 and 30 mg L-1) and 4 ratios of P and K (0.5, 1.0, 1.5 and 2.0 times the content of these nutrients in the original Hoagland solution). For the variables height, SPAD value, activity and concentration of TSP, it was considered the addition of time as a factor for sub-plot. The experimental unit consisted of a polyethylene pot with two soybean plants. The application of TIBA was performed by foliar sprays at the developmental stage \"V5\", while supplying the nutrient solution started from the 4th day after emergence. TIBA caused a reduction of plant height and dry mass of roots, and promote increased SPAD values during the transition between vegetative and reproductive phases. This retardant did not affect the total values of number of pods and grains, grain weight and average weight of 100 grains, however, it showed effects on some of their constituents (increase in the number of secondary branches and a decrease in the number of pods and grains, and grain weight of the branches). The ratio of P and K equal to 2.0 adversely affects in most of the variables and some of their constituents (height, root dry weight, number of primary branches and total number of pods and grains, grain number from stem, grain weight from stem and total weight), while the ratio of 1.5 affects the number of pods from branches and total average weight of 100 grains, respectively.